Figure. Phylogenetic tree based on the Leptospira flaB gene sequence. The sequences obtained in this study are indicated in boldface and have been deposited in DDBJ/GenBank/EMBL (accession numbers indicated). The sequences of rat isolates are derived from a previous study (9). Sequence alignments were conducted by using MEGA4 software and ClustalW (www.megasoftware.net), and phylogenetic distances were calculated by using MEGA4 software and the neighbor-joining method. All 4 PCR products belong to L. interrogans; 2 are closely related to serovar Losbanos, 1 to serovar Manilae, and 1 is not associated with strains or serovars included in our analysis. Microscopic agglutination test results indicate infecting serogroups. L. borgpetersenii serovar Tarassovi had the highest titer in patients 307 and 486, but this finding can be explained by a cross-reaction. Scale bar indicates nucleotide substitutions per site.